1. Field of the Invention
The present invention relates to an adhesive material for use in residue confirmation, which is applied in advance to an object to be cleaned for confirmation of a residue remaining on the object after cleaning, and a method for confirmation of a residue remaining on the object after cleaning using the adhesive material, in cleaning of objects to be cleaned such as machine parts.
2. Description of the Related Art
Examples of the machine parts include parts cut from an extruded material and parts with a material formed by casting as a starting material. Machine parts are generally manufactured by subjecting the starting material to milling, drilling, tapping, polishing or other machining, and further surface treatment. Cleaning of the machine parts is performed while they are being machined, or before or after they are machined, or after the surface treatment. The cleaning is aimed at removing a casting mold release agent or sand mold adhering to the starting material, chips produced by machining, foreign particles caused by conveyance of an intermediate workpiece in process of machining, foreign particles deposited by surface treatment, etc. from an object (workpiece) to be machined or treated.
The workpiece after machining, which is to be cleaned by a cleaning apparatus, is referred to as the object to be cleaned, and sometimes simply as the object. The workpiece with chips thereon, as the object to be cleaned, is conveyed to the cleaning apparatus.
Most of the dirt adhering to the object to be cleaned, that is, the residue remaining on the object to be cleaned, is chips produced during cutting work of machine parts. The shape of the chips changes depending on the cutting methods and conditions, and includes a helical shape, thin sheet rectangular piece, spiral, disc or other irregular shapes. These chips may fall into a recess, screw hole, water hole, crossing hole, etc. provided in a workpiece when the workpiece is machined. Furthermore, because the chips have irregular shapes, edges of the chips pierce the object to be cleaned or get caught in a hollow portion in the object to be cleaned, so that the chips and the object to be cleaned may be joined together.
Examples of the cleaning apparatus include a spray cleaning machine. The spray cleaning machine is configured such that an object to be cleaned is put into the cleaning machine, and then cleaning liquid increased in pressure by a high-pressure pump is jetted from a nozzle to thereby wash the object.
Within the spray cleaning machine, the chips fall off the object under the dynamic pressure of the jet jetted from the nozzle. Then the chips leave the object along with the flow produced by the jet jetted from the nozzle. However, the chips joined to the object are hard to remove with a jet of the sprayed cleaning liquid.
As a related-art technology, a method is known (see, for example, Japanese Published Unexamined Patent Application No. 2011-206619), in which cleaning water used for cleaning components is filtered by a filter and dust accumulated on the filter is directly observed with a microscope or the like to evaluate the cleanliness of various components, such as machine parts or optical components, after cleaning.
The Japanese Published Unexamined Patent Application No. 2011-206619 discloses the technology for counting dust particles captured by the filter or observing the shapes of the particles with an optical microscope.
Furthermore, the cleaning capacity evaluation can be also conducted by causing the residue adhering to the object after cleaning to collect on the filter and measuring the total mass and size.
In this case, firstly, the mass of the filter in a dry state is measured. The object is left at rest on a clean sink, and then clear liquid is poured on the object. The poured liquid is collected, and filtered by the filter to collect a residue. The filter is dried, and the mass of the filter is measured again. The difference in the mass of the filter before and after filtration is expressed as the amount of residue. The smaller the amount of residue is, the higher the cleaning capacity evaluation is.
Meanwhile, in the spray cleaning machine, in order to improve the cleaning capacity, it is important that the jet jetted from the nozzle enters the area on the object where dirt is stuck.
Therefore, if the area on the object where chips remain can be specified, rather than merely detecting the amount of the residue remaining on the object after cleaning, the nozzle can be positioned or the moving path of the nozzle can be changed so that a water jet strongly hits a specified position. Furthermore, the change in the position or moving path of the nozzle allows an improvement in cleaning capacity of the cleaning apparatus.
While the above is a description with the spray cleaning machine as an example, specifying the area where chips remain is essential for improving the cleaning capacity even in other cleaning apparatuses, such as a cleaning apparatus in which the object to be cleaned is placed in a water jet and cleaned by devising the flow structure of the water jet. In other words, specifying the area of the object after cleaning where chips remain is useful for improving the cleaning capacity regardless of the cleaning method.
However, in the method in which the cleaning liquid used for cleaning the object to be cleaned is filtered by the filter to thereby collect and evaluate the residue adhering to the object, the area on the object where chips remain cannot be specified.
In order to specify the area of an object to be cleaned where chips remain, therefore, there is a possible approach, in which the object with chips intentionally applied thereto is put into a spray cleaning machine to confirm which area of the object after cleaning the chips remain in. The chips used here are chips produced in an actual process line or chips of the same material as the chips produced in an actual process line. This is because the rigidity and shapes of the chips vary depending on the cutting conditions and the joining forms of the chips to the object change. For this reason, the chips to be applied to the object are preferably of the same material as the object.
In this case, because the chips and the object to be cleaned are of the same material, the surface colors of the chips and the object to be cleaned are the same or similar. Furthermore, because the object to be cleaned is manufactured by machining an extrusion or casting as a starting material, the surface of the object includes a casting surface, extrusion surface, and machined surface. Regardless of the casting method, generally, the casting surface has very fine uneven shapes, and when it is visually observed, shades in a fine pattern on the uneven surface caused by external light are observed. Furthermore, the pattern made by a rotary cutting tool in contact with the workpiece is observed on the machined surface. Also, if the machined surface has a casting defect, shades are made on the defective places of the machined surface. In this manner, the surface of the machine parts has generally almost the same color and various fine shades.
To specify the area where chips remain after cleaning, it is necessary to find the chips of the same color as the object while lying on the surface of the object which is wide and has various shades. However, it is very hard to distinguish between the chips and the shades on the object. Therefore, there still remains the problem that the area on the object after cleaning where chips remain cannot be specified.